The present invention relates to an apparatus for removing dross ridges from metal workpieces, such as slabs, blooms, billets, or the like.
In the production of steel by, for example, the continuous casting process, the continuous cast length emerging from the caster is cut into desired lengths to form separate metal workpieces, which are commonly referred to as slabs, blooms, or billets. The separate workpieces are then subjected to subsequent processing, as by rolling, to form a finished steel product.
The cutting operation as described above is conventionally performed by means of a flame or torch, wherein a jet of high purity oxygen is directed against the workpiece while it is heated to the oxygen ignition temperature. The resulting exothermic chemical reaction between the iron and oxygen produces slag or waste, which consists of iron oxide, metallic iron and other alloy elements. This slag or waste is in the molten state, and it is displaced during the cutting operation and a portion thereof forms a ridge of the material along the lower edge of the cut end. Upon cooling, the material solidifies and adheres to the workpiece surface along the bottom surface adjacent the cut end, and forms what is commonly called a "dross ridge".
The formation of the dross ridges on the workpiece presents problems in the further processing thereof. For example, a dross ridge may drop off in the reheat furnace, which requires that it then be removed, thus involving additional labor. Also, in the event the dross ridge remains adhered to the workpiece during reheating, it is laminated into the steel during rolling of the workpiece, resulting in an inferior product.
Heretofore, the dross ridges resulting from a torch cutting operation have been removed by a process involving inverting the workpiece and removing the dross ridges with scarfing torches. However, the required additional handling of the workpiece entails additional equipment and labor. Mechanical chippers or chisels have been employed for this purpose, but this also is a labor intensive process.
U.S. Pat. No. 4,859,126 discloses an apparatus for efficiently removing dross ridges immediately after the workpiece has been cut, and which comprises a dross removal beam having a generally flat outer surface and a cutting edge along each of its two opposite sides. The blade is positioned to extend across and below the workpiece path of travel, and the blade is rotatable between a neutral position wherein the blade is below the pass line of the workpiece, and opposite tilted positions in which one or the other of the cutting edges engages the lower dross carrying surface of the workpiece, and so that each cutting edge is adapted to engage and "deburr" a dross ridge on the workpiece.
The dross removal beam as disclosed in the above-referenced patent is primarily used to deburr rectangular steel slabs that are formed by the most widely used steel solidifying process, i.e. continuous casting. Inherent in the continuous casting process is the fact that the broad surface of the slab to which the dross ridge adheres may be bulged, resulting in a slightly convex or concave surface profile. The amount of the bulge will vary based on size of the slab and other factors, and it can sometimes be severe enough to prevent continuous contact between the cutting edge of the dross removal beam along the entire surface of the slab. In addition to bulging, there may be other profile distortions in the slab caused by mechanical or thermal influences which can also prevent adequate contact of the cutting edge with the surface of the slab. These conditions can adversely affect the performance of the dross removal beam, lowering its overall reliability.
It is accordingly an object of the present invention to provide a dross removal beam of the described type which effectively overcomes the above noted limitations of the prior beam.
It is a more particular object of the present invention to provide a dross removal beam which is able to effectively remove a dross ridge along a convex or concave surface of the slab.